Place cream of coconut on a plate and toasted coconut on another plate.
Lightly dip the rim of a margarita or rocks glass in the cream of coconut and let any excess drip off. (You may want to spread the agave around with a brush or your finger — the coconut will only stick to that.)
Roll the rim of the glass in the toasted coconut to coat. Add ice to the prepared glass.
In a cocktail shaker filled with ice, add tequila, triple sec, lime juice, cream of coconut and coconut simple syrup.
Shake vigorously, then strain into the prepared glass.